Yield trials are an important way for producers to look at a hybrid's performance in several locations, over several years and environments. Yield is one component of the trials. In 2004, 2005 and 2006 all of the trials were conducted by USDA or university personnel. Some of the trials prior to those years were coordinated by the National Sunflower Association. New in 2005 was a disease rating for Sclerotinia stalk rot, downy mildew and rust. Seed companies may have additional trial and disease rating information.